Radio apparatus



June 23, 1931.- L. w. STONEQUIST 1,811,099

RADIO APPARATUS Filed April 2, 1925 2 Sheets-Sheet 1 v bl Fig. 6

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June 23, 1931. w, STQNEQUIST 1,811,099

RADIO APPARATUS Filed April 2, 1923 2 Sheets-Sheet 2 Fatented June 23, 1931 UNITED STATES PATENT oFFICE LAWRENCE W. STONEQUIST, OF CHICAGO, ILLINOIS, ASSIGNOR F ONE-HALF TO CHARLES ROTTUM, OF CHICAGO, ILLINOIS RADIO APPARATUS Application filed. April 2, 1923. Serial No. 629,350.

This invention relates to improvements in radio apparatus and has for its object to provide a new and improved apparatus of this kind. It is desirable in the ordinary radio apparatus to ground the aerial when the apparatus is not in use so that if the aerial is struck by lightning there will be no danger of fires or injury to the apparatus. The invention has as a further object to provide means for automatically grounding the aerial when the apparatus is not in use. The invention has as a further object to provide a safety type rheostat in the circuit that automatically protects from an excess amount of current. The invention has other objects which are more particularly pointed out in the accompanying descrip tion.

Referring now to the drawings:

Fig. 1 is a diagrammatic view of one form of device embodying the invention.

Fig. 2 is an enlarged plan view of the rheostat.

Fig. 3 is a rear view of the rheostat shown in Fig. 2.

Fig. 4 is a sectional view taken on line 4.--4 of Fig. 3.

Fig. 5 is a perspective view of the spring for the contact arm shaft. 7

Fig. 6 is a sectional view taken on line 6-6 of Fig. 3.

v Fig. 7 is asectional view taken on line 77 of Fig. 2.

Like numerals refer to like parts throughout the several figures.

In the drawings I have shown one particular diagram of circuits but it is of course evident that any other arrangement may be used and I have simply illustrated this par-.

ticular constructionto make my invention clear. In this construction I have shown the B battery, the dry cell 2, the tube 3, the ear piece 4, the 23 plate vernier condenser 5, the variometers 6 and 7, the aerial inductance 8 between them, the grid leak 9,

the aerial'lO and the rheostat 11, all connected in circuit. The rheostat 11 is provided with a resistance coil 12, one end of which is connected to the terminal 13, said terminal connected by the conductor 14 with the screw 21 then tightened..

wound upon a thin strip 32made of suitthe battery which is connected withthe filament 15 of the tube 3. The tube is provided with the plate 3 and the grid 3 This filament 15 is connected with a removable fuse 16 on the rheostat, said fuse being connected with the terminal. 17, said terminal being connected with the rotating arm 19 of the rheostat. This rotating arm makes a contact with the different sections of the resistance coil 12 to vary the resistance through the filament 15. The arm 19 is controlled by the handle 20 (seeFig. 2). I prefer to arrange means for elastically holding the arm 19 in contact with the different sections of the resistance coil. In the construction 5 shown the arm 19 is connected by a set screw 21 with the shaft .22. This shaft has a shoulder 23 and there is a spring washer or other spring device 2 1 between the shoulder 23 and a suitable stop. When it is desired to attach the arm 19 the shaft 22 is pushed in to compress the spring and the arm 19 pushed against the rheostat coil and It will thus be seen that there will then be a tension due to spring 2 1 which tends to hold the rheostat arm 19 in contact with the resistance coil. This washer may also be used to makethe electrical connection between the fuse 16 and the rheostat arm 19 through the shaft 22. This is accomplished by providing the washer with a laterally project- .ing extension having the bent portion 25 which engages the bolt or terminal 17 which is electrically connected to the fuse 16. The fuse 16 is removable so that a fuse of any desired capacity may be used and a new fuse placed in position when the fuse is burned. I have shown for this purpose a fuse held by the spring clips 27 and 28. The spring clip 28 is connected to the projecting member 29 which in turn is electrically connected to the bolt or terminal 17 The rheostat frame and the resistance coil may be arranged in any desired manner. In the particular construction shown I have illustrated the frame 30 of the rheostat as made of in- I sulating material and as having at one end the annular projection 31. The coil itself is able insulating material. This strip is formed into circular'shape and attached to the frame 30 set over the portion of the frame and abutting against the annular projection 31 (see Fig. 4). Two conducting sections and 3 are provided between the ends of the resistance and are insulated upon each other. The conducting section or con tact 33 is connected by the conductor 35 with the aerial 10 while the conducting sectional contact 3% is connected by conductor 36 with the ground 37 (see Fig. l). lVhen the clevice is not in use the rheostat arm 19 connects the contacts 33 and 3e. hen in this position the circuit through the radio apparatus is broken and he aerial 10 is connected directly to the ground 37. If now it is desired to use the apparatus the rheostat 19 is turned to engage the coils of the resistance and is moved to the desired position where the proper resistance is in circuit. The circuit through the rheostat will then be as follows: from the battery to the filament 15, then through the fuse 16, thence the terminal or bolt 17 and the washer 24 to the shaft 22, thence through the rheostat arm 19 and thence through that portion of the resistance coil in circuit and thence to the terminal 13 and back to the battery. hen it is desired to shut off the apparatus th rlieostat arm is turned to its off position. hen in this position the circuit through the tube filament is broken and the rheostat arm connects the contacts 33 and 34. The aerial 10 is then directly grounded, the circuit being through conductor 35 to contact 33, thence across the rheostat arm to contact 3% and thence by conductor 36 to ground 37. It will thus be seen that the act of shutting elf the apparatus automatically connects the aerial to the ground so that nothing is leftfor the user to do. \Vhile the user always shuts off the apparatus when he gets through he will very often forget to ground the aerial if some extraneous means is used. For this purpose by means of this device the mere turning off of the apparatus grounds the aerial so that there can be no danger of the aerial being left ungrounded so that lightning can injure the apparatus or set the build ng on fire. As soon as the rheostat arm is moved to complete the circuit enough the filament 15 the aerial is disconnected from the ground. It often happens that through wrong connections and other ways too much current passes through the filament of the tube and it is destroyed. By placing the fuse 16 on the rheostat as herein shown this trouble is avoided because this fuse i always in connection with the filament 15 and is arranged to break the circuit before the current can injure the apparatus. If more than one rheostat is used in the apparatus it is only necessary to use the first rheostat for grounding the aerial and the extra contacts on the other rheostat may be used for other purposes.

I have described in detail a particular construction embodying the invention but it is of course evident that the parts may be varied in many particulars without departing from the spirit of the invention as embodied in the claims hereto appended and I, therefore, do not limit myself to the particular construction shown.

I claim:

1. A radio apparatus comprising an aerial, a tube, a rheostat having a resistance coil, a movable arm adapted to connect any desired portion of said resistance in circuit with the filament of said tube, said rheostat provided with two contacts insulated from each other and from the resistance, one of said contacts connected with the aerial and the other with the ground, the arm'of the rheostat when in its off position connecting said contacts so as to ground the aerial.

2. A radio apparatus comprising an aerial, a tube, a rheostat adapted to connect the filament of the tube in an electrical circuit and vary the resistance in the circuit there.- through and means associated with said rheo stat for automatically grounding the aerial when the circuit through the filament of the tube is broken by shutting oif the current.

3. A radio apparatus comprising an aerial, a tube, a resistance, a movable arm adapted to connect the filament of said tube in circuit with said resistance and means associated with said arm when itis moved to its oil posit-ion to ground said aerial.

at. A radio apparatus comprising a rheostat, a tube, a circuit making and breaking device on said rheostat for connecting the resistance thereof in circuit with the tube filament and disconnecting it therefrom, a second circuit making and breaking device on said rheostat and a single movable element for successively controlling and maintaining operative either of said circuit making and breaking devices.

5. A radio apparatus comprising a rheostat, a tube, a circuit making and breaking device on said rheostat for connecting the resistance thereof in circuit with the tube filament and disconnecting it therefrom, a second circuit making and breaking device on said rheostat and a single rotatable arm adapted when operating on the first circuit making and breaking device to maintain the resistance in circuit with said tube and when moved to the second circuit making and breaking device to break the circuit through said tube and resistance and maintain a separate circuit.

Signed at Chicago, county of Cook and State of Illinois, this 16th day of March,

LAWVRENCE- XV. STONEQUIST. 

